Hylobates pileatus

Short phrases of bi-phasic hoots ("oo-wa")
of hiccup-like quality, simple hoots and short trills. Bi-phasic hoots consist of
notes alternatingly produced during exhalation and inhalation, as in H. agilis.
Short series of inhalation hoots only or exhalation hoots only also occur. Short
phrases are produced by either sex, but more frequently and usually louder by males.
Female great call with an acceleration-type climax, like H. muelleri, with
similar, fast bubbling note production, and without becoming slower at the end of
the great call. Great call usually longer than in H. muelleri, and first great
call notes usually more drawn out (the muelleri great call shown in the sonageramm
above is unusually long). Male produces coda, beginning halfway through the great
call. Male solo song bouts and duet song bouts.